Re: [PATCH v8 10/22] perf record: Introduce --threads=<spec> command line option

["Bayduraev, Alexey V" <alexey.v.bayduraev@linux.intel.com>]

Hi,

On 30.06.2021 20:28, Arnaldo Carvalho de Melo wrote:
> Em Wed, Jun 30, 2021 at 06:54:49PM +0300, Alexey Bayduraev escreveu:
>> Provide --threads option in perf record command line interface.
>> The option can have a value in the form of masks that specify
>> cpus to be monitored with data streaming threads and its layout
>> in system topology. The masks can be filtered using cpu mask
>> provided via -C option.
> 
> Perhaps make this --jobs/-j to reuse what 'make' and 'ninja' uses?
> 
> Unfortunately:
> 
> [acme@quaco pahole]$ perf record -h -j
> 
>  Usage: perf record [<options>] [<command>]
>     or: perf record [<options>] -- <command> [<options>]
> 
>     -j, --branch-filter <branch filter mask>
>                           branch stack filter modes
> 
> [acme@quaco pahole]$
> 
> But we could reuse --jobs
> 
> I thought you would start with plain:
> 
>   -j N
> 
> And start one thread per CPU in 'perf record' existing CPU affinity
> mask, then go on introducing more sophisticated modes.

As I remember the first prototype [1] and 
[2] https://lore.kernel.org/lkml/20180913125450.21342-1-jolsa@kernel.org/

introduces: 

--thread=mode|number_of_threads

where mode defines cpu masks (cpu/numa/socket/etc)

Then somewhere while discussing this patchset it was decided, for unification,
that --thread should only define CPU/affinity masks or their aliases.
I think Alexei or Jiri could clarify this more.

> 
> Have you done this way because its how VTune has evolved over the years
> and now expects from 'perf record'?

VTune uses only --thread=cpu or no threading.

Regards,
Alexey

> 
> - Arnaldo
>  
>> The specification value can be user defined list of masks. Masks
>> separated by colon define cpus to be monitored by one thread and
>> affinity mask of that thread is separated by slash. For example:
>> <cpus mask 1>/<affinity mask 1>:<cpu mask 2>/<affinity mask 2>
>> specifies parallel threads layout that consists of two threads
>> with corresponding assigned cpus to be monitored.
>>
>> The specification value can be a string e.g. "cpu", "core" or
>> "socket" meaning creation of data streaming thread for every
>> cpu or core or socket to monitor distinct cpus or cpus grouped
>> by core or socket.
>>
>> The option provided with no or empty value defaults to per-cpu
>> parallel threads layout creating data streaming thread for every
>> cpu being monitored.
>>
>> Feature design and implementation are based on prototypes [1], [2].
>>
>> [1] git clone https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git -b perf/record_threads
>> [2] https://lore.kernel.org/lkml/20180913125450.21342-1-jolsa@kernel.org/
>>
>> Suggested-by: Jiri Olsa <jolsa@kernel.org>
>> Suggested-by: Namhyung Kim <namhyung@kernel.org>
>> Acked-by: Andi Kleen <ak@linux.intel.com>
>> Acked-by: Namhyung Kim <namhyung@gmail.com>
>> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
>> ---
>>  tools/perf/builtin-record.c | 355 +++++++++++++++++++++++++++++++++++-
>>  tools/perf/util/record.h    |   1 +
>>  2 files changed, 354 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index 2ade17308467..8d452797d175 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -51,6 +51,7 @@
>>  #include "util/evlist-hybrid.h"
>>  #include "asm/bug.h"
>>  #include "perf.h"
>> +#include "cputopo.h"
>>  
>>  #include <errno.h>
>>  #include <inttypes.h>
>> @@ -122,6 +123,20 @@ static const char *thread_msg_tags[THREAD_MSG__MAX] = {
>>  	"UNDEFINED", "READY"
>>  };
>>  
>> +enum thread_spec {
>> +	THREAD_SPEC__UNDEFINED = 0,
>> +	THREAD_SPEC__CPU,
>> +	THREAD_SPEC__CORE,
>> +	THREAD_SPEC__SOCKET,
>> +	THREAD_SPEC__NUMA,
>> +	THREAD_SPEC__USER,
>> +	THREAD_SPEC__MAX,
>> +};
>> +
>> +static const char *thread_spec_tags[THREAD_SPEC__MAX] = {
>> +	"undefined", "cpu", "core", "socket", "numa", "user"
>> +};
>> +
>>  struct record {
>>  	struct perf_tool	tool;
>>  	struct record_opts	opts;
>> @@ -2723,6 +2738,70 @@ static void record__thread_mask_free(struct thread_mask *mask)
>>  	record__mmap_cpu_mask_free(&mask->affinity);
>>  }
>>  
>> +static int record__thread_mask_or(struct thread_mask *dest, struct thread_mask *src1,
>> +				   struct thread_mask *src2)
>> +{
>> +	if (src1->maps.nbits != src2->maps.nbits ||
>> +	    dest->maps.nbits != src1->maps.nbits ||
>> +	    src1->affinity.nbits != src2->affinity.nbits ||
>> +	    dest->affinity.nbits != src1->affinity.nbits)
>> +		return -EINVAL;
>> +
>> +	bitmap_or(dest->maps.bits, src1->maps.bits,
>> +		  src2->maps.bits, src1->maps.nbits);
>> +	bitmap_or(dest->affinity.bits, src1->affinity.bits,
>> +		  src2->affinity.bits, src1->affinity.nbits);
>> +
>> +	return 0;
>> +}
>> +
>> +static int record__thread_mask_intersects(struct thread_mask *mask_1, struct thread_mask *mask_2)
>> +{
>> +	int res1, res2;
>> +
>> +	if (mask_1->maps.nbits != mask_2->maps.nbits ||
>> +	    mask_1->affinity.nbits != mask_2->affinity.nbits)
>> +		return -EINVAL;
>> +
>> +	res1 = bitmap_intersects(mask_1->maps.bits, mask_2->maps.bits,
>> +				 mask_1->maps.nbits);
>> +	res2 = bitmap_intersects(mask_1->affinity.bits, mask_2->affinity.bits,
>> +				 mask_1->affinity.nbits);
>> +	if (res1 || res2)
>> +		return 1;
>> +
>> +	return 0;
>> +}
>> +
>> +static int record__parse_threads(const struct option *opt, const char *str, int unset)
>> +{
>> +	int s;
>> +	struct record_opts *opts = opt->value;
>> +
>> +	if (unset || !str || !strlen(str)) {
>> +		opts->threads_spec = THREAD_SPEC__CPU;
>> +	} else {
>> +		for (s = 1; s < THREAD_SPEC__MAX; s++) {
>> +			if (s == THREAD_SPEC__USER) {
>> +				opts->threads_user_spec = strdup(str);
>> +				opts->threads_spec = THREAD_SPEC__USER;
>> +				break;
>> +			}
>> +			if (!strncasecmp(str, thread_spec_tags[s], strlen(thread_spec_tags[s]))) {
>> +				opts->threads_spec = s;
>> +				break;
>> +			}
>> +		}
>> +	}
>> +
>> +	pr_debug("threads_spec: %s", thread_spec_tags[opts->threads_spec]);
>> +	if (opts->threads_spec == THREAD_SPEC__USER)
>> +		pr_debug("=[%s]", opts->threads_user_spec);
>> +	pr_debug("\n");
>> +
>> +	return 0;
>> +}
>> +
>>  static int parse_output_max_size(const struct option *opt,
>>  				 const char *str, int unset)
>>  {
>> @@ -3166,6 +3245,9 @@ static struct option __record_options[] = {
>>  		     "\t\t\t  Optionally send control command completion ('ack\\n') to ack-fd descriptor.\n"
>>  		     "\t\t\t  Alternatively, ctl-fifo / ack-fifo will be opened and used as ctl-fd / ack-fd.",
>>  		      parse_control_option),
>> +	OPT_CALLBACK_OPTARG(0, "threads", &record.opts, NULL, "spec",
>> +			    "write collected trace data into several data files using parallel threads",
>> +			    record__parse_threads),
>>  	OPT_END()
>>  };
>>  
>> @@ -3179,6 +3261,17 @@ static void record__mmap_cpu_mask_init(struct mmap_cpu_mask *mask, struct perf_c
>>  		set_bit(cpus->map[c], mask->bits);
>>  }
>>  
>> +static void record__mmap_cpu_mask_init_spec(struct mmap_cpu_mask *mask, char *mask_spec)
>> +{
>> +	struct perf_cpu_map *cpus;
>> +
>> +	cpus = perf_cpu_map__new(mask_spec);
>> +	if (cpus) {
>> +		record__mmap_cpu_mask_init(mask, cpus);
>> +		perf_cpu_map__put(cpus);
>> +	}
>> +}
>> +
>>  static int record__alloc_thread_masks(struct record *rec, int nr_threads, int nr_bits)
>>  {
>>  	int t, ret;
>> @@ -3198,6 +3291,235 @@ static int record__alloc_thread_masks(struct record *rec, int nr_threads, int nr
>>  
>>  	return 0;
>>  }
>> +
>> +static int record__init_thread_cpu_masks(struct record *rec, struct perf_cpu_map *cpus)
>> +{
>> +	int t, ret, nr_cpus = perf_cpu_map__nr(cpus);
>> +
>> +	ret = record__alloc_thread_masks(rec, nr_cpus, cpu__max_cpu());
>> +	if (ret)
>> +		return ret;
>> +
>> +	rec->nr_threads = nr_cpus;
>> +	pr_debug("threads: nr_threads=%d\n", rec->nr_threads);
>> +
>> +	for (t = 0; t < rec->nr_threads; t++) {
>> +		set_bit(cpus->map[t], rec->thread_masks[t].maps.bits);
>> +		pr_debug("thread_masks[%d]: maps mask [%d]\n", t, cpus->map[t]);
>> +		set_bit(cpus->map[t], rec->thread_masks[t].affinity.bits);
>> +		pr_debug("thread_masks[%d]: affinity mask [%d]\n", t, cpus->map[t]);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int record__init_thread_masks_spec(struct record *rec, struct perf_cpu_map *cpus,
>> +					  char **maps_spec, char **affinity_spec, u32 nr_spec)
>> +{
>> +	u32 s;
>> +	int ret = 0, nr_threads = 0;
>> +	struct mmap_cpu_mask cpus_mask;
>> +	struct thread_mask thread_mask, full_mask, *prev_masks;
>> +
>> +	ret = record__mmap_cpu_mask_alloc(&cpus_mask, cpu__max_cpu());
>> +	if (ret)
>> +		goto out;
>> +	record__mmap_cpu_mask_init(&cpus_mask, cpus);
>> +	ret = record__thread_mask_alloc(&thread_mask, cpu__max_cpu());
>> +	if (ret)
>> +		goto out_free_cpu_mask;
>> +	ret = record__thread_mask_alloc(&full_mask, cpu__max_cpu());
>> +	if (ret)
>> +		goto out_free_thread_mask;
>> +	record__thread_mask_clear(&full_mask);
>> +
>> +	for (s = 0; s < nr_spec; s++) {
>> +		record__thread_mask_clear(&thread_mask);
>> +
>> +		record__mmap_cpu_mask_init_spec(&thread_mask.maps, maps_spec[s]);
>> +		record__mmap_cpu_mask_init_spec(&thread_mask.affinity, affinity_spec[s]);
>> +
>> +		if (!bitmap_and(thread_mask.maps.bits, thread_mask.maps.bits,
>> +				cpus_mask.bits, thread_mask.maps.nbits) ||
>> +		    !bitmap_and(thread_mask.affinity.bits, thread_mask.affinity.bits,
>> +				cpus_mask.bits, thread_mask.affinity.nbits))
>> +			continue;
>> +
>> +		ret = record__thread_mask_intersects(&thread_mask, &full_mask);
>> +		if (ret)
>> +			goto out_free_full_mask;
>> +		record__thread_mask_or(&full_mask, &full_mask, &thread_mask);
>> +
>> +		prev_masks = rec->thread_masks;
>> +		rec->thread_masks = realloc(rec->thread_masks,
>> +					    (nr_threads + 1) * sizeof(struct thread_mask));
>> +		if (!rec->thread_masks) {
>> +			pr_err("Failed to allocate thread masks\n");
>> +			rec->thread_masks = prev_masks;
>> +			ret = -ENOMEM;
>> +			goto out_free_full_mask;
>> +		}
>> +		rec->thread_masks[nr_threads] = thread_mask;
>> +		if (verbose) {
>> +			pr_debug("thread_masks[%d]: addr=", nr_threads);
>> +			mmap_cpu_mask__scnprintf(&rec->thread_masks[nr_threads].maps, "maps");
>> +			pr_debug("thread_masks[%d]: addr=", nr_threads);
>> +			mmap_cpu_mask__scnprintf(&rec->thread_masks[nr_threads].affinity,
>> +						 "affinity");
>> +		}
>> +		nr_threads++;
>> +		ret = record__thread_mask_alloc(&thread_mask, cpu__max_cpu());
>> +		if (ret)
>> +			goto out_free_full_mask;
>> +	}
>> +
>> +	rec->nr_threads = nr_threads;
>> +	pr_debug("threads: nr_threads=%d\n", rec->nr_threads);
>> +
>> +	if (rec->nr_threads <= 0)
>> +		ret = -EINVAL;
>> +
>> +out_free_full_mask:
>> +	record__thread_mask_free(&full_mask);
>> +out_free_thread_mask:
>> +	record__thread_mask_free(&thread_mask);
>> +out_free_cpu_mask:
>> +	record__mmap_cpu_mask_free(&cpus_mask);
>> +out:
>> +	return ret;
>> +}
>> +
>> +static int record__init_thread_core_masks(struct record *rec, struct perf_cpu_map *cpus)
>> +{
>> +	int ret;
>> +	struct cpu_topology *topo;
>> +
>> +	topo = cpu_topology__new();
>> +	if (!topo)
>> +		return -EINVAL;
>> +
>> +	ret = record__init_thread_masks_spec(rec, cpus, topo->thread_siblings,
>> +					     topo->thread_siblings, topo->thread_sib);
>> +	cpu_topology__delete(topo);
>> +
>> +	return ret;
>> +}
>> +
>> +static int record__init_thread_socket_masks(struct record *rec, struct perf_cpu_map *cpus)
>> +{
>> +	int ret;
>> +	struct cpu_topology *topo;
>> +
>> +	topo = cpu_topology__new();
>> +	if (!topo)
>> +		return -EINVAL;
>> +
>> +	ret = record__init_thread_masks_spec(rec, cpus, topo->core_siblings,
>> +					     topo->core_siblings, topo->core_sib);
>> +	cpu_topology__delete(topo);
>> +
>> +	return ret;
>> +}
>> +
>> +static int record__init_thread_numa_masks(struct record *rec, struct perf_cpu_map *cpus)
>> +{
>> +	u32 s;
>> +	int ret;
>> +	char **spec;
>> +	struct numa_topology *topo;
>> +
>> +	topo = numa_topology__new();
>> +	if (!topo)
>> +		return -EINVAL;
>> +	spec = zalloc(topo->nr * sizeof(char *));
>> +	if (!spec) {
>> +		ret = -ENOMEM;
>> +		goto out_delete_topo;
>> +	}
>> +	for (s = 0; s < topo->nr; s++)
>> +		spec[s] = topo->nodes[s].cpus;
>> +
>> +	ret = record__init_thread_masks_spec(rec, cpus, spec, spec, topo->nr);
>> +
>> +	zfree(&spec);
>> +
>> +out_delete_topo:
>> +	numa_topology__delete(topo);
>> +
>> +	return ret;
>> +}
>> +
>> +static int record__init_thread_user_masks(struct record *rec, struct perf_cpu_map *cpus)
>> +{
>> +	int t, ret;
>> +	u32 s, nr_spec = 0;
>> +	char **maps_spec = NULL, **affinity_spec = NULL, **prev_spec;
>> +	char *spec, *spec_ptr, *user_spec, *mask, *mask_ptr;
>> +
>> +	for (t = 0, user_spec = (char *)rec->opts.threads_user_spec; ; t++, user_spec = NULL) {
>> +		spec = strtok_r(user_spec, ":", &spec_ptr);
>> +		if (spec == NULL)
>> +			break;
>> +		pr_debug(" spec[%d]: %s\n", t, spec);
>> +		mask = strtok_r(spec, "/", &mask_ptr);
>> +		if (mask == NULL)
>> +			break;
>> +		pr_debug("  maps mask: %s\n", mask);
>> +		prev_spec = maps_spec;
>> +		maps_spec = realloc(maps_spec, (nr_spec + 1) * sizeof(char *));
>> +		if (!maps_spec) {
>> +			pr_err("Failed to realloc maps_spec\n");
>> +			maps_spec = prev_spec;
>> +			ret = -ENOMEM;
>> +			goto out_free_all_specs;
>> +		}
>> +		maps_spec[nr_spec] = strdup(mask);
>> +		if (!maps_spec[nr_spec]) {
>> +			pr_err("Failed to alloc maps_spec[%d]\n", nr_spec);
>> +			ret = -ENOMEM;
>> +			goto out_free_all_specs;
>> +		}
>> +		mask = strtok_r(NULL, "/", &mask_ptr);
>> +		if (mask == NULL) {
>> +			free(maps_spec[nr_spec]);
>> +			ret = -EINVAL;
>> +			goto out_free_all_specs;
>> +		}
>> +		pr_debug("  affinity mask: %s\n", mask);
>> +		prev_spec = affinity_spec;
>> +		affinity_spec = realloc(affinity_spec, (nr_spec + 1) * sizeof(char *));
>> +		if (!affinity_spec) {
>> +			pr_err("Failed to realloc affinity_spec\n");
>> +			affinity_spec = prev_spec;
>> +			free(maps_spec[nr_spec]);
>> +			ret = -ENOMEM;
>> +			goto out_free_all_specs;
>> +		}
>> +		affinity_spec[nr_spec] = strdup(mask);
>> +		if (!affinity_spec[nr_spec]) {
>> +			pr_err("Failed to alloc affinity_spec[%d]\n", nr_spec);
>> +			free(maps_spec[nr_spec]);
>> +			ret = -ENOMEM;
>> +			goto out_free_all_specs;
>> +		}
>> +		nr_spec++;
>> +	}
>> +
>> +	ret = record__init_thread_masks_spec(rec, cpus, maps_spec, affinity_spec, nr_spec);
>> +
>> +out_free_all_specs:
>> +	for (s = 0; s < nr_spec; s++) {
>> +		if (maps_spec)
>> +			free(maps_spec[s]);
>> +		if (affinity_spec)
>> +			free(affinity_spec[s]);
>> +	}
>> +	free(affinity_spec);
>> +	free(maps_spec);
>> +
>> +	return ret;
>> +}
>> +
>>  static int record__init_thread_default_masks(struct record *rec, struct perf_cpu_map *cpus)
>>  {
>>  	int ret;
>> @@ -3215,9 +3537,33 @@ static int record__init_thread_default_masks(struct record *rec, struct perf_cpu
>>  
>>  static int record__init_thread_masks(struct record *rec)
>>  {
>> +	int ret = 0;
>>  	struct perf_cpu_map *cpus = rec->evlist->core.cpus;
>>  
>> -	return record__init_thread_default_masks(rec, cpus);
>> +	if (!record__threads_enabled(rec))
>> +		return record__init_thread_default_masks(rec, cpus);
>> +
>> +	switch (rec->opts.threads_spec) {
>> +	case THREAD_SPEC__CPU:
>> +		ret = record__init_thread_cpu_masks(rec, cpus);
>> +		break;
>> +	case THREAD_SPEC__CORE:
>> +		ret = record__init_thread_core_masks(rec, cpus);
>> +		break;
>> +	case THREAD_SPEC__SOCKET:
>> +		ret = record__init_thread_socket_masks(rec, cpus);
>> +		break;
>> +	case THREAD_SPEC__NUMA:
>> +		ret = record__init_thread_numa_masks(rec, cpus);
>> +		break;
>> +	case THREAD_SPEC__USER:
>> +		ret = record__init_thread_user_masks(rec, cpus);
>> +		break;
>> +	default:
>> +		break;
>> +	}
>> +
>> +	return ret;
>>  }
>>  
>>  static int record__fini_thread_masks(struct record *rec)
>> @@ -3474,7 +3820,12 @@ int cmd_record(int argc, const char **argv)
>>  
>>  	err = record__init_thread_masks(rec);
>>  	if (err) {
>> -		pr_err("record__init_thread_masks failed, error %d\n", err);
>> +		if (err > 0)
>> +			pr_err("ERROR: parallel data streaming masks (--threads) intersect\n");
>> +		else if (err == -EINVAL)
>> +			pr_err("ERROR: invalid parallel data streaming masks (--threads)\n");
>> +		else
>> +			pr_err("record__init_thread_masks failed, error %d\n", err);
>>  		goto out;
>>  	}
>>  
>> diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h
>> index 4d68b7e27272..3da156498f47 100644
>> --- a/tools/perf/util/record.h
>> +++ b/tools/perf/util/record.h
>> @@ -78,6 +78,7 @@ struct record_opts {
>>  	int	      ctl_fd_ack;
>>  	bool	      ctl_fd_close;
>>  	int	      threads_spec;
>> +	const char    *threads_user_spec;
>>  };
>>  
>>  extern const char * const *record_usage;
>> -- 
>> 2.19.0
>>
>